From: "Peter Boyce" peterboyce at myjaring.net> on 2005.08.25 at 16:46:09(13324)Mike

Burnt soil is made by heaping a mound of moist (but not wet) clay-rich
subsoil over a a wood fire. We do it here by digging a shallow pit (1m x 1m
x 25 cm deep) filling it with wood (large branches, 4 x 4 off-cuts, &c) that
is then set alight and allowing it to burn slowly for an hour (much as yu
would set a BBQ) then carefully mounding the soil over the smouldering wood.
The whole is allowed to burn for 2 - 3 days at the end of which the now
semi-baked is removed and broken up. The final product is granular/small
lump (1 - 2 cm) size. What it adds to the mix is a rich source of phosphates
and microelements, some good structure (since the granular parts are quite
hard) and also a source of silica.

Wilbert is absolutely correct. We find that none of the indigenous Bornean
Amorphs are dormant for long. In fact, many species are effectively in
leaf all the time in that a new leaf is emerging as the old leaf is in its
final stages of senescence. We grow in coconut peat, coconut fibre, washed
coarse sand and a small proportion of burnt soil, water copiously and also
feed copiously. The minimum at the nursery here is 22 C (c. 72 F) and the
maximum 34 C (c. 93 F).

Peter, can you speak to the "burnt soil" component of your potting medium?
What does it add to the party? How is it prepared? Just guessing here,
but is charcoal anywhere close to a reasonable substitute?